The invention concerns a permutation lock in which a plurality of rotary dials are retained in selected positions by means of a dial spring.
A permutation lock of this type is known from German DE-P No. 29 40 166. There, the dial spring includes arms extending from an integral base plate which corresponds in width to the width of the bottom of the housing. The arrangement is such that always a pair of arms are engaging each dial and act as locking springs. The base plate is relatively material intensive; a double quantity of the material is used per permutation lock. The dual arm locking engagement imparts more resistance, so that the zero-setting that may be overcome in one direction but not in the other direction (or perhaps only with extra effort), is no longer clearly distinct in "feel" from the other locking positions. The base plate is situated between the lock housing and an insert comprising the internal apparatus (dials, slide, etc.) and the front plate. A plurality of inwardly bent stop tabs project from angled edges of the base plate and abut against the projections of the insert to retain the base plate.
It is an object of the present invention to provide a permutation lock which is formed of less material and which maintains the distinctive "feel" when the dials have been rotated to a zero-setting.